Barcode system

Almost every item purchased in a shop has a barcode on it.  These look like a series of thick and thin black lines.  The barcode contains details about the product, the manufacturer and the country of origin.  It also contains a check digit, so that the computer can validate that the data has been read in correctly.

The first section, highlighted blue identifies the country.  The yellow section identifies the manufacturer, the orange section is the product code and the red section is the check digit.

The barcode details are scanned into the system by a laser scanner on the till.  The check digit is calculated and compared to the scanned one.  The till beeps if they match.

The barcode is sent to the store's central computer system.   This computer system contains the current price of the product in the database.

The price is sent from the central computer to the Electronic Point of Sale till ( EPOS), which processes and prints the customer's itemised bill and receipt.

It is important for students to understand that the price is NOT in the bar code.  Local shops charge different prices to supermarkets.  Also prices go up and down - if the price were in the barcode, the shop would have to remove all of the packaging to replace it with the new barcode!!

Now to processing ...